Pneumatic tire



y 1960 F. P. BALDWIN ETAL 2,944,578

PNEUMATIC TIRE Filed May 51, 1955 5 Sheets-Sheet 1 a o w ua '2 w LL mumsP. BALDWIN ROBERT M. moms BY 10 4M ATTORNEY July 12, 19 F. P. BALDWINETAL 2,944,578

PNEUMATIC TIRE Filed May 51, 1955 5 Sheets-Sheet 2 Rllll 2 91.5%ISOBUTYLENE 2.5% ISOPREIIE nun sass ISOBUTYLENE 2% ISOPRENE |.o

WT. I. OHLORIIIE (III THE FORM OF SULFURYL CHLORIDE) Ill REACTIUNMIXTURE FRANCIS P. BALDWIN ROBERT M. moms '"VENTORS BY W ATTORNEY F. P.BALDWIN ET AL 2,944,578

PNEUMATIC TIRE July 12, 1960 5 Sheets-Sheet 3 Filed May 31, 1955 F I 6.III

IIOL a. uusnuamou or 0mm roman IODINE NUMBER OF ORIGINAL POLYMER m m$.52 @525 E 5; 5

July 12, 1960 F. P. BALDWIIRI ETAL 2,944,578

PNEUMATIC TIRE s Sheets-Shet 4 Filed May 31, 1955 FIGJIZ.

IT. I. filORlRE II THE ORLORIRATED POLYI IER INVENTORS FRARCiS P.BALDWIN ROBERT M. THOMAS BY W ATTORNEY July 12, 1960 F. P. BALDWIN ETAL2,944,578

PNEUMATIC TIRE Filed May 51, 1955 5 Sheets- Sheet 5 Francis P. BaldwinRobert M. Thomas Inventors By 7/9? X E Attorney 2344,98 V PNEUMATICTIREFrancis P. Baldwin, comm and Ro'be'rtM. Tlio as,

-West'field, NJL, assignors to-Esso Research andEugi' neering Company, acorporation of Delaware Filed May"31,19:5, Ser. No. 512,182 3 24 Claims.(Cl. 151-330) This invention relates toVuIcaniZabIerubbery polymericcompositions which are chlorinated ,copolymers of iso-olefins andmulti-olefins and to the preparation of such compositions. Italsorelates to compositions con- .taining chlorinated copolymersofiso-olefins and multiolefins together with other rubbery materials,such as synthetic and natural rubbers. The copolyrners of the presentinvention generally contain'a major proportion, preferably at least 70weight percent of iso-olefins, and a minor proportion, preferably notmore than about 30 weight percent of multi-olefi'ns.

Copolymers. of the above general where the copolymer contains aboutiii-99.5% -(preferably about 9599.5%) of a C -C iso+olefin such asisobutylene with about 15-05% (preferably about Si-0.5 weight percent)of a multi-olefin of about 4-14 carbon type, especially atomsarecommonlyreferred to in patents and literature as butyl rubber or G R-Irubber (Government Rubber- Isobutylene) and, for example, isreferred toas butyl ,rubber in patents and in the textbook SynthetieRubber by G. S.-Whitby (1954. Edition by John Wiley & Sons, Inc), pages 608-609, etc. 1The expression butyl rubber as employed in'the specification and claimsis intended toinclude copolymers containing about, 90-99% by weight ofan iso-olefinof about 4-7 carbon atoms and about 10-l ofaconjugatedmulti-olefin of-aboutA- -lt) carbon atoms. The preparation ofbutyl-typerubbers is described in US. Patent 2,356,128 to Thomas et-al.

and also in other patents as well as in literature; In

general, the rubbercomprises the reaction pro'duct of'a Cg-C iso-olefin(preferably isobutylene) 'with. a cg-Cm (preferably a C -C conjugateddiolefin such as isoprene, butadiene, dimethyl butadiene, piperylene,etc. The reaction product of isobutyleneand isoprene is pref re e v 1Heretofore, it has not been possible tojproduce a :butyl rubber.which'is curable with certain basic metal compounds such asbivalentQmetal oxides (preferably zinc oxide) in the absence ofsulfurwithoutproducing a rubber whi ch does not withstand heat aging and/or isdegraded into polymers ofiundesirablylow molecular weight. It has alsonot been possible to produce heat stable butyl rubbers (which are notdegraded, asgto molecularweight) which are covulcanizable withcertainother natural and synthetic rubbers, especially highly unsaturatedrubbers. s 1

Attempts have been made in the prior art to produce improved butylrubbers by chlorinating therubberso as to contain above about 25chlorine and especially about 40-60% chlorine sinceit was believed that25% chlorine absorption was undesirably low for physical 2,944,578 7Patented July 12, 19.60

not commercial- In fact, no chlorination procedures or.

procedures combining oxidation and-chlorination as proposed in .thepriorart have produced a thermally stable, high molecular weight, rubberypolymer which is 'curable with zinc oxide .andmayin fact be covulcanizedwithother'known rubbers, both natural andsynthetic. Another proposal ofthe prior art has been to ;,bro'- minate the butyl rubber. However, nomatter what quantities of bromine are introduced into-the-polymer,

the .heat aging resistance of the resulting butylrubber leaves much tobe desired. r e f 1 By the present invention it is now possible toproduce butyl type rubbers of excellent heat aging resistance. This isdone by chlorinating the rubber in a manner which does not degrade themolecular weight' thereof, but sufliciently to produce a rubber whichretains-its tensile strength upon heat aging. The chlorinated butylvrubbers of the present invention do not greatly difler-in curing rate ascompared to naturalrubber andother synthetic rubbers such as GRS rubberand thus maybe covulcanized therewith by the use of zinc oxide and/ orsulfur or other known vulcanizing agents. I Theinvention will bedemonstrated hereinafter-with reference to the accompanying drawings inwhich:-

. -Figu-re I is a graphical comparison-showing the heat agingsuperiorityof the chlorinated butyl rubber of'the present invent-ion'ascompared to broniinated-butyl rubher; the comparison being one oftensile strengths of the two respective rubbers heat aged at 300 F. forvarious time intervals up to 1.4 hours;

i Figure II is a graph depicting the-percent chlorine -in'twochlorinated butyl rubbers-plotted against the percent chlorine in thereaction mixture in the formof Figure III is a graph depicting a line ofclosest agreeirnent for various butyl rubbers of isobutylene and ,;iso-

strength. However, such attempts have resulted in badly 'degrading themolecular weight, viscosity and rubbery characteristics of the butylrubber. Furthermore, when butyl rubber drops so badly thattherubberyff'characteristics are so seriously impaired that the material'is1" prene as determined by plotting the iodine number-and the molepercent'unsaturation of theorig inalpolymer against the percentchlorinein the final chlorinated polymer andis for the purpose ofshowing thatthe relationship between the latter two is linear, 7

.Fig'ure IV, is a graph depicting the elfect of chlorinati on onthe'molecular weight of a butyl rubber contain- 'in'g 96.84 Weight percentisobutylene and 3.16 weight "percent isoprene; and

I Figure V 'is a cross-sectional view in perspective of a pneumatic;tubeless tire employing therein the chlorinated'butyl rubber of thepresent invention whereinlthe tire is depicted as being mounted on aconventional-tire Wheel rim. 1

' According to the present. invention, rubbery materials o'fthe type ofbutyl rubber are chlorinated soas to conleast about 1.0 weight percent)combined chlorine, but not more than about X weight percent combinedchlorine wherein: e

"i 35.46L- i m and:

.L=mole percent of the multi-olefin-inthe' polymer rM =molecularweightof the iso-olefin M molecular weight of the multi-olefin 35-.46=atomicweight of chlorine Restated, there should be at least about 0.5 weightpercent of combined chlorine in the polymerbutnot more than about 1atom'of chlorine combined insthe lpolyiner per molecule of multi-olefinpresent therein; not more than about'one atom of combined chlorine pertain about at least 0.5 weight percent,(preferablyjat 3 double bond inthe polymer.

0.25-0.60 times the mole percent unsaturation of the polymer. I,Suitable chlorinating agents which may be employed are molecularchlorine, alkali metal hypochlorites (preferably sodium hypochlorite),sulfur chlorides (particularly oxygenated sulfur chlorides), pyridiniumchloride perchloride, N-chlorosuccinimide, alpha-chloroacetoacetanilide,tri-chlorophenol chloride, N-chloroactamide, beta-chloro-methylphthalimide, and other common chlorinating agents. Thepreferredchlorinating agents are molecular chlorine and even moreespecially sulfuryl chloride. The chlorination is advantageouslyconducted at to 100C. and preferably, at about 20 to 80 C. for-about oneminute to several hours. However, the temperatures and times areregulated to chlorinate the rubbery copolymer to the extentabovementioned.

The chlorination may be accomplished in various ways. One processcomprises preparing a solution of the copolymer as above, in a suitableinert liquid organic solvent such as an inert hydrocarbon oradvantageously halogenated derivatives of saturated hydrocarbons, exam.-ples of which are hexane, heptane, naphtha, kerosene, straight runmineral spirits, benzene, toluene, naphthalene, chlorobenzene,chloroform, trichloroethane, carbon tetra chloride, etc., and addingthereto the chlorine or In other words, the maximum mole percent ofcombined chlorine should be about other chlorinating agent, preferablyin solution, such as dissolved in an alkyl chloride, carbon tetrachloride, etc.

Other variations, which are not as preferred, comprise employing thechlorinating agent in the form of a gas, and contacting the gas witheither a solution of the copolymer or the solid copolymer per se.

For example, if elemental chlorine is employed, it is mostadvantageously 'added in an alkyl chloride or carbon tetra chloridesolution rather than in the gaseous state.

The use of elevated or depressed pressures is optional since atmosphericpressure is satisfactory although the pressure may vary, de-

pending upon the foregoing temperatures and times from about 1 to- 400p.s.i.a.

The copolymer to be chlorinated is advantageously first dissolved in asolvent such as any of the foregoing, especially a saturated hydrocarbonor a completely chlo I 'rinated hydrocarbon. Particularly preferredsolvents for particular chlorinating agents are as follows: carbon tetrachloride and/or chloroform for molecular chlorine, paraffinichydrocarbons and/or carbon tetra chloride and/or aromatics such asbenzene as non-polar solvents for chlofrination with certain,chlorinating agents, especially sul- "furyl chloride.

However, any ofthe above-listed chlorinating agents may be employed withan inert polar solvent for the copolymers providing theconditionsof:chlorination and amounts of the chlorinating agent are carefullycontrolled.

In one process for the preparation of a butyl rubber isoprene, atrelatively low temperatures; preferably from about 0 C. to about -180 C.or lower; an advan tageous range being from about 40 C. to about 160 0.,preferably from about -80 C. to about l20 C.

sulfur especially in the presence of alkylated tellurium thiocarbamates,such as telluriurn diethyl dithiocarbamate, or in the presence oforganic sulfides, particularly of the tetra alkyl thiuram sulfide type,etc.

Butyl rubber compositions may also be prepared wherein the cure iseiiected in the presence of such materials as p-dinitrosobenzene,pq'uinone dioxime, etc, and their various homologs and derivatives knownfor this purpose. The cure may also be accomplished in the presence ofsuch compositions as (1) sulfur and a zinc dialkyl polythiocarbamate (2)sulfur, lead oxide, and p-quinone dioxime (3) sulfur, ben-zothiazylsulfide and p-quinone dioxime, (4) p-quinone dioxime dibenzoate, leadoxides and sulfur, (5) selenium and/or tellurium containingcompositions, etc. h

The copolymer, which has been cured has good elastic limit, tensilestrength, abrasion resistance and flexure resistance. Thew copolymer hasa mole percent unsaturation of about 0.5. to about 25-35, preferablybetween about 05-100. As well as the above, the copolymer before curingmay be further compounded with various 'fillers, pigments, plasticizers,and anti-oxidants, etc. Also, the use of other activators, vulcanizationaccelerators, curing agents, etc. for special applications for butyltyperubbers is known in the art and disclosed in various patents andpublications. Therefore, the particular com- "pounding disclosed in thespecific examples herein is to be construed as merely representaive orillustrative, is not intended to be all-inclusive, and in many instancesgcertain o-f the materials may be omitted and other materials "addedwithout departing from the essence of the instant invention.

The vulcanization of chlorinated butyl rubber or covulcanization ofchlorinated butylatype rubber with other rubbery materials according tothe instant invention may be from about 250 F. to about 450 lF.,preferably at about 280-350 F.for from several seconds up to about '5hours or more. Normally the vulcanization or covulcanization is fromabout 10 minutes to about 2 hours depending upon the desired use and thenature and "amount of the added rubber when co-vulcanized with thechlorinated butyl rubber. Furthermore, although for most uses theoptimum vulcanization conditions are from about 5-120 minutes at about280-350 F., the particular compounding desired will require a change invul- -'canizi-ng conditions as will the presence or absence of sulandvulcanization accelerators in addition to or in lieu of vulcanization inthe presence of basic metal compounds such las bivalent metal oxides ofthe type of zinc oxide. For example, when the cure is in the presence ofsulfur and an accelerator (e.g. tetra methyl thiuram disulfide,tellurium diethyl dithiocarbamate, etc.),

' -'the requisite curing time at the same temperature will "'tive formany purposes at 270-320 F. for about 5-60 :With the preferred reactantsbeing about 1-10 parts by The reaction is conducted in the presence of aFriedel- Crafts catalyst such as aluminum chloride, titaniumtetrachloride, !boron trifluoride, uranium chloride, etc. dissolved inan alkyl halide, such as ethyl or methyl chloride, or dissolved incarbon disulfide or equivalent solvent. inger molecular weight betweenabout 20,000 to about 100,000 or somewhat higher. This corresponds to aviscosity average molecular weight of about 150,000 to about onemillion. The preferred viscosity average molecular weight is from about250,000 to about 1,000,- 000 or more.

:bery in nature, has the property of being curable When so prepared, thematerial is rub- The resulting copolymer preferably has a Staud-.

be less than in the case of employing a zinc-oxide cure pre se. In theformer instance the cure would .be effecminutes whereas in the latterinstance a more desirable cure is at about 260-340 F. at about 15minutes to about 2 hours depending upon the desired use.

One particularly advantageous butyl rubber is produced weightof isopreneand about 99-90 parts by weight of isobutylene and the mixture of thesereactants is cooled 10 a temperature within the range of about to 'of acatalyst comprising a solution of an aluminum halide.

- C. and then polymerized by the addition thereto For further specificdetails as to other processes for the production of butyl rubbers,reference may be had to Us. Patents12, 356,128; 2,384,975; 2,399,672;2,418,912; 2,607,764 and the literature.

; The'invention will be better understood from the following' exampleswherein reference will be made to the :drawingsi- In the-examples;unless otherwise indicated, the chlorination temperature is roomtemperature (25 (2.), 'the' pressure isia'tmospheric "and the timeaisz30minutes. r Y X, j

; XAM L -The result of a number ofruns areillustratedinfFig. 1 in whichA, Cand E are sulfur-curedhalogenated butyl rubbers and B, D and F arenine oxide-cured halogenated butyl rubbers. Also, A and B butyl rubberscontain 1.25 wt.:fpercent chlorinewhereas Irubbers C and D contain2.5-wt; percent bromine and rubbers-E and F. contain ;1.25 wt. percentbromine. 3 s 3' R un #1 r The butyl rubber employed in all instances inFigure 1 is a copolymer containing 97% isobutylene and 3% isoprenehaving a viscosity average molecular weight of 320,000. The reactants ofisobutylene and isoprene are mixed in a ratio of about 94 parts byweight of isobutylene .and about 6 parts by weight'of isoprene andaredissolved in liquidmethyl chloride. To this admixture is added; a.solutionof aluminum chloridedissolved in liquid methyl chloride insufiicient quantities tocorrespond te -about 0.5 part by weight of A1C1per 100parts by weight of re"- actants. The polymerization is thenconducted at about ;100 FL, the solvent strippedolf, the catalyst killedby water-washing, and the rubberypolymerrecovered therefrom. Thepolymer-is then -dissolved-in-liquid ethyl "chloride to forma 20%'-solution containing 100 parts by weight of copolymer. The copolymer-isthen admixed t l. results when cured at 287 F. .for the times desigwith2.5 partsby weight of chlorinedissolved in liquid ethyl chloride andstirred for 2 hours under conditions of diffused light while keeping theethyl chloride in the liquid state. -The unreacted chlorineisneutralizedwith a 20% water solution of sodium carbonate: The rubberychlor'inated copolymer is recovered by filtration, contains 1.25% byweight of chlorine and has a-viscosity average molecular weight of320,000.-- Run #2 The above general procedure is then repeated byemploying bromine dissolved in ethyl chloride; and, by varying theamounts of bromine between about 2-7 parts by weight of bromine in theethyl chloride, per '100'parts" by weight of the copolymer, twodifierent portions ofbrominated butyl rubber are obtained; one portioncontaining ..1.25 weight percent bromine and the other portion.containing 2.5 weight percent bromine. I r

. The above samples of chlorinatedand brominated butyl rubbers are thendivided into two additional samples. and eachis compounded bysmilling.with 50parts vby weight of carbon black, 10pa1ts by'weight 'zincnox ideper 100 parts by weight of the vcopolymer and were vulcanized for 20minutes at 330 F.' The vulcanizates obtained are designated asvulcanizates B, D, and .F in Figure 1. T the other portionof thesecopolymers is added 50 parts by weight carbon black, 10 parts by'weightzinc oxide, 3 parts'by weight sulfur, 2 parts'ofstearic' acid 14 hours,the chlorinated butyl rubbers (A and B) withstand heat agingsatisfactorily inthat their tensile strength is only slightly altered(slightly lowered in the case of the sulfur-cured chlorinated butylrubber (rubber-A) and slightly raised in the case oft-he zincoxide-cured -.chlorinated butyl rubber (rubber .B).. -However, the

brominated butyl rubber does not .heatage, satisfactorily and loses fromabout 800to 1000.p.s.i..intensilestrength (as shown by thecurvesdepicting butyl rubbers C to F) which for rubbers having 'air'initial tensile strength .of about 1370 p.s.i. and .2200.p.s;i, isa;serious EXAMPLE '2' r,

A polymer containing about 97% isobutylene and. 3%

isoprene as prepared in Example 1 and having a viscosity 5 averagemolecular'weight of 320,000was dissolved in hexane to form a solution.To this polymeric solution, 20 weight percent (based on the polymer) ofliquid sulfuryl chloride'was added as the chlorinating agent and theresulting chlorinated interpolymer was 10 precipitated with acetone,collected, and redissolved'in hexane three times and ultimately driedand analyzed and found to have a viscosity average molecular weight of320,000 and to contain 1.4% chlorine based on the polymer. The compositewas then: divided into 2 por- 15 'tions as was a commerciallyobtainable'butyl rubber containing 2.5-3.0 wt. percent bromine, and the'following.compositions were prepared;

. Parts byWelght Rubber Rubber Rubber Rubber '13. B "'0 'D'"'Chlorlnated Butyl Rubber --10o----- 10o .Brominated ButylRubber 100 q A100 Carbon Black. g 50 50 50 50 Zinc Oxide..:.. 5 5 6 '5 Sulfur 1 1'Tellurium" Dlethyl'Dlthio- I -carbamate...- .1 1 TStearic'Acid 1 1 1 1nated, were as follows:

;--. 7 I Rubber Rubber mt... Rubber Curing Time,'Min 20 so 12o e0Tensile Strength, p.s.i 1,530 2,420 1,710 2,335

"The above compositions, A,-'B, ,C, and D, were then f'heataaged undermore drastic conditions for 16 hours at 320 F; in a mold and the resultswere asfollows: 1

Rubber I O I I a 0 Rubber Rubber Rubber A B I D Tensile Strength, p.s.i340 2 1,320 g 1,940 2,075 -.Tensile Strength retalned,% 22.2 53.6 11a88.9

A comparison of the above shows the'superiority or chlorinated .butylrubber. in composition with oxide andalsdwhen in composition with'bothzinc oxide, Qsuliur and a vulcanization accelerator as rcompared'tobrominated butyl rubber made up inidentical compositions. f

I When these above compositions werevulcanized'at their optimum, curingtime. at 287 F., the chlorinated 'butyl rubbers -C and D exemplified ahigher modulus floi'of elastic'ity at 300% elongationand'comparabletensile strength. Also, when thesesame compositionswereheat- "aged for 16 hours at 320 F., the tensile strength or thebrominated butyl rubbers Aland-B dIo ped'tobetween 22.2-53.6% of theiroriginal tensile strength which is an extremely serious loss; 'whereasthe chlorinated butyl rubbers C and D were not substantially afiectedthat the tensile. strength was either raised. or lowered only slightly;(Le; a gain in tensile strength of 13%. d' a loss in'tensile strength of11.1%, respectively).

5- a EXAMPLE 3 The identical procedure is {followed for Example and theresulting butyl rubber containing 1.4% chlorine based'on thepolymer'iscompared to commercial to brominated butyl rubber.

Rubber E Rubber 1:

Chlorinated Butyl Rubber o Brominated Butyl Rubber 100 Carbon Black(SRF) 50 50 Zin Oxide 10 10 Sulfur l 1 Tellurium Diethyl'Dithiocarbamate1 1 4-methyl-2,6-ditertiary phenol 1 0. 25 0.25

1 Antioxidant.

The above butyl rubber compositions E and F are then cured for 60minutes at 320 F. and have the following tensile strength:

Rubber E-2400 p;s.i. Rubber F--2280 p.s.i.

The compositions are then aged in a tensile pad mold for 24 hours at 320F. and the following tensile properties are obtained:

Rubber E F Tensile Strength, p.s.i 2, 260 1, 220 Percent Retention ofTensile Strength 85 68. 5 '25 Modulus of Elasticity 300% Elongation 1,620 780 A comparison of the above shows the superiority of chlorinatedbutyl rubber when heat aged as compared The fact that an antioxidant(4-methyl-2,6-di-tertiary phenol) is added slightly improves the heataging characteristics of the chlorinated butyl rubber but does notappreciably alter the poor heat aging characteristics of the brominatedbutyl rubber.

It is a further discovery of the present invention that when a non-polarsolvent is employed with certain chlorinating agents, the amount ofchlorine introduced into the polymer is much more easily controlled.This is particularly noticeable when non-polar solvents such ascompletely chlorinated hydrocarbons, aliphatic saturated hydrocarbons orpetroleum streams containing saturated aliphatic hydrocarbons, aromatichydrocarbons, etc., such as naphtha, n-heptane, hexane, cyclohexane,pentane, benzene, toluene, etc. are employed with sulfur-chlorides,especially sulfuryl chloride. For instance, sulfuryl chloride may beemployed according to the above when carbon tetrachloride is the butylrubber solvent where as when using such materials asunsymmetrical'halogenated organic compounds such as alkyl chlorides,

g closely controlled conditions are required. 7 For example,

employing sulfuryl chloride with a non-polar solvent such as carbontetrachloride, the amount of chlorinating agent added is not nearly ascritical as when sulfuryl chloride with a polar solvent such aschloroform is used; and the resulting amount of chlorine in achlorinated copolymer containing 97-975 wt. percent isobutylene and2.5-6.0 wt. percent isoprene is maintained within the range of about0.5-2.0 wt. percent although relatively large amounts of sulfurylchloride in carbon tetrachloride are used. The above principle isgraphically illustrated in Figure II which will be described in thefollowing example.

EXAMPLE 4 In both instances of Figure II, only about 1.2-1'.5

atoms of chlorine reacted with the copolymer per about 16 atoms ofchlorine in the form of sulfuryl chloride present in the reactionmixture. The amount of sulfuryl chloride was then increased to about 1.5times the amount of chlorine above mentioned without changing thecombined chlorine content of the polymer appreciably. In Figure II, thereaction between the sulfuryl j chloride and the butyl rubber wasallowed to proceed at C. for 90 hours (although the reaction wassubstantially complete in 10-15 minutes) in order to as Run A Thirtygrams of an interpolymer containing about 98.0% isobutylene and 2.0%isoprene having a viscosity aver-age molecular weight of 330,000 weredissolved in 480 grams of carbon tetrachloride and treated for 2 hoursat room temperature with 3 mls. of liquid sulfuryl chloride containing10.5 wt. percent chlorine based on -the 'interpolymer. The polymer wasthen precipitated from solution with acetone, filtered,.redissolved inn-hexane, again precipitated with acetone, redissolved and tfiltered,etc., in order to. purify the product. The rubbery polymeric compositionwas then dried and analyzed for chlorine content and found to contain1.19% chlorine.

The rate of reaction of the chlorine with the interpolymer was asfollows:

The polymer was then compounded as follows:

Parts by weight Polymer 10.0 Zinc oxide 5 Carbon black -40 Stearic acid,2

Three portions of the above were cured as follows with the followingresults:

Tensile Modulus at Elongation Cure, min. at 300 F. Strength 300% Elonca-Percent (p.s.i.) tion in p.s.i.

The above data indicate that a satisfactory elongation is obtained whenthe rubber is cured for about 10-12 minutes or more but that the tensilestrength of the rubber improvedconsiderably when cured for 30-40 min-Utes or longer.

. Run B The same general procedure of Run A was repeated except that theinterpolymer had a viscosity average molecular weight of 340,000 andcontained 97.5% isobutylene and 2.5% isoprene. To a solution of theabove -interpolymer in 300 milliliters of carbon tetrachloride was added5 milliliters of SO Cl to give a resulting polymer compositioncontaining 1.4% chlorine by weight based onethe interpolymer after '15minutes. The polymer was allowed to continue reaction for variousperiods Oftime at ro0m tempera'ture"(25 C.) and was recovered byrepeated precipitation with acetone and re-solution in n-hexane,re-precipitation etc., and was ultimately dried in an over under 28inches of mercury vacuum at70 C. andanalyzed as follows:

Reaction time (min): Percent chlorine in polymer g g EXAMPLE 5liar-preparing butyl rubbers -(of isobutylene. and isoprene) A, B and Cappearing in Figure III, 30 grams'of butyl rubbers having respectively(a) 1 mol percent unsaturation (98.79 weight percent isobutylene),l(b1.7 mol percent unsaturation (97.94 weight percent isobutylene), and (c)2.07 mol percent unsaturation (97.49 weight percent isobutylene) weredissolved in-BOO milliliters of carbon tetrachloride (a non-polarsolvent). Ten milliliters of liquid S Cl containing'28 weight percentchlorine based on weight of the polymer was'added, whichadditionconstitutes a very large excess. The reaction .was conducted for 30minutes at room temperature C.) and the resulting chlorinated butylrubbers were recovered according to the procedure of Example 4, Run 2.

By plotting, in Figure III, the iodine number of the original polymeragainst the percent of chlorine in the final polymer, the line ofclosest agreement corresponds to about 0.71 weight percent chlorine inthe finished polymer per mol percent unsaturation (iodine number'times0.147) of the original polymer. This corresponds to about 1.12 atoms ofchlorine per molecule of multi-olefin in-the polymer after completereaction. Thus it is shown that regardless of the iodine number of theoriginal polymer, by employing sulfuryl chloride in a nonpolar solventas the chlorinating medium, a ratio is maintained of approximately oneatom of chlorine (i.e., 1.12 atoms) combined with the polymer for eachmolecule of multi-olefin therein, which ratio is very desirable for thepurposes of the present invention.

EXAMPLE 6 I A butyl-type rubbery copolymer containing 96.84 wt. percentof isobutylene. and 3.16 wt. percent of isoprene 7 equals X wherein:

and having a viscosity average molecular weight of 320,-

000 was dissolved in chloroform (a polar solvent) to form a 10 wt.percent solution. To this polymeric solution, various amounts of liquidsulfuryl chloride were added as hereinafter indicated in Table I and asshown in Figure IV. copolymer and sulfuryl chloride was at 25 C. for 24hours and the resulting chlorinated interpolymcr was precipitated fromsolution with acetone, collected, redissolved in hexane, etc., for threesuccessive times and ultimately dried and found to contain the followingamounts of combined chlorine and molecular weights:

Referring now to Figure IV, which comprises a graph including the data.from Table I, it is shown that when sulfuryl chloride is employed tochlorinate butyl rubber in' a polar solvent (chloroform), thechlorination must be carefully controlled to prevent degradation ofthemolecular weight of the rubber. For example, from the graph for theabove tested butyl rubber (containing 96.84 1

weight percent isobutylene and 3.16 weight percent isoprene), it isshown that when more than about 1.61.8 weight percent of chlorine wasintroduced into the polymer the molecular weight thereof became rapidlyand drastically lowered. Referring back to Table I,'it willtu)v be notedthat about 1.4 percent chlorine represents about 0.89 atom of chlorineper molecule offmulti-olefin in the polymer,pwhereas 1.6 percentchlorine represents In all instances, the reaction between the 40 about1 atom of chlorineper1molecule; of multi-olefin in L g the rubberypolymer. Thus, it has been demonstrated 0.8'weight percent chlorinet Thepolymer was .then com;

that approximately the --maxirnuni amount of chlorine permissible,whereby toobtain a, chlorinated butyl rubher without degrading themolecular weight ofthe poly mer, is about one atom of chlorine permolecule of multiolefin -in'the polymer, which corresponds to a ratio ofa ut one. atom of chlorine per double bond in said Po y e Employingtheformula given above for pp o tely the preferred maximumpermissiblechlorine content in the polymer, the maximum weight percent of chlorinelecular weight of isoprene and wherein: M .molec'ular weight ofisobutylene; M =mo L mol percent isoprene 3. 16.

therefore: I

X: 1oo-2.s 5s.1 +2.6(68.1 +3546) X and: v a

'X=1.61 weight percent combined chlorine EXAMPLE 7 Weight percentPolymer 100 Zinc oxide 5 Carbon black 40 Stearic acid 2 7 i TensileModulus at Elongation Cure, min. at 300 F. Strength 300% Elonga-(percent) (p.s.l.) tion (p.s.i.)

EXAMPLE 8 I A solution in carbon tetrachloride of a copolymer having aviscosity average molecular weight of 340,000 and containing 97.5%isobutylene and 2.5% isoprene was prepared to contain 100 grams ofpolymer per liter of solution; To this solution, at room temperatureunder conditions of diffused light, 1.6 weight percent of chlorine wasadded in a solution of carbon tetrachloride having a concentration'of0.025 gram .of chlorine permilliliter of solution. The chlorine wasadded in four equal increments. 'The first increment added imparted ayellowish shade. of color to: the polymer solution which bleachedoutwithin'afew minutes. Approximately 1 mole of hydrogen .chlorinewasevolved per mole of chlorine added andrlthehydrogen chloride evolutionbegan almost instantly. The last increment of chlorine added imparted ayellowish-green color .to the polymer solution which likewise bleachedout. The composite was allowed to standZ hoursv at iroom temperature indiffused light and the polymer was recovered from this solution byprecipitation with methyl alcohol followedby drying in a vacuum oven for12 hours at 50 C. and was found to contain atom in the polymer molecule.

pounded with 40 parts by weight carbon black, 2 parts by.weight'stearic'acid, and5 parts by weight zinc oxide per l00 parts by weight ofthekcopolymer, Was heated for 40 minutes at 300 F., was found to becompletely The procedure of Example 8 was repeated except that 2.41% ofchlorine was added to the copolymer containing 97.5% isobutylene and2.5%.isoprene at oncerather than incrementally, and the resultingcopolymer had a chlorine content of about 1.2% by weight. The polymerwas also admixed with the, same quantities of carbon black,

'stearic acid and zinc oxide, and vulcanized under the same conditionsas in Example 4 and the vulcanizate was found to have substantially thesame physical propertiesas the vulcanizateof Example 8.

The same general procedure was employed as in Run A-A, except that 4.8-weight percent of chlorine was added and the resulting copolymer had achlorine content of about 2.4. weight percent. The rubber was found to.have decreased in viscosity excessively and have become so excessivelydegraded as to be unusable as a rubber. From the above runs in Example9, it was determined that the atoms of combined chlorine shouldnotappreciablyexceed the number of molecules of added conjugateddiolefin (such as isoprene). Since, in the above runs of Example'9, 2.5weight percent of isoprene was employed, the maximum amount of chlorineperniissihle would. be. roughly .about 1.2% and it isfor this reasonthat run A-A employing 1.2% .by weight of combined chlorine wassatisfactory, whereas run BB employing 2.4% by.weight combined.chlorineywas unsatisfactory.

" Applying the above formula for more closely calculating approximatelythe maximum amount of combined chlorine permissible, said amountexpressed as weight percent of combined chlorine in the polymer equals Xwherein: I

wherein: M =M.W. of isobutylene, M i-Mgw. of isoprene and L=rnol.percent isoprene I =2.5 =2.5 =2.0 6 mole percent therefore and:

X=1.28 weight percent chlorine rine combined with hydrogen to evolve ashydrogen chloride, and the other atom apparentlyreplaced a hydrogenTherefore, in order' to obtain a given percent of chlorine in thepolymer, ap proximately double this amount of chlorine must be added.

V The following examples are also illustrative of the foregoingEXAMPLEIO 7 A solution in liquid ethyl chloride of a copolymercontaining about 92 parts by weight isobutylene and 8.0. parts by weightof isoprene having a viscosity average molecular weight of 240,000 isprepared in a concentrav tion of 100 grams of polymer per liter ofsolution. To this solution at room temperature under conditions ofdifiused light, approximately 6.0 grams of chlorine as a solution of0.03% grams chlorine per milliliter of chloroform is added and themixture is allowed to stand for one hour at room temperature. Thepolymer is recovered from the solution by precipitation with methylalcohol, followed by drying in an oven overnight at 60 C. When 100 partsby weight of the resulting polymer is compounded with 40 parts by weightof carbon black, 2 'parts by weight of stearic acid and 5 parts byweight of Zinc oxide and heated for one hour at 290 F., it is notdegraded in viscosity and withstands heat aging at 300 F. for twentyhours satisfactorily. The amount of combined chlorine in the chlorinatedbutyl rubber is about 3.00 weight percent.

Applying the above formula for calculating approxi mately the maximumamount of combined chlorine permissible, said amount expressed as weightpercent of combined chlorine in the polymer equals X wherein:

' 100-L M.+L 1ir2+35.46 wherein: M =M.W. of isobutylene, M =M.W. ofisoprene and m sea; L- m0le percent isoprene 8 .0 8.0 -6.59

therefore:

and:

X =3.96 weight percent chlorine EXAMPLE 11 The same general procedure asfor Example 10 is repeated by employing instead of theisobutylene-isoprene copolymer, the following:

(1) Coplymer containing about 95% isobutylene and 5 isoprene with 2.5%combined chlorine.

(2) Copolymer containing about 94% isobutylene and 6% cyclopentadienewith 2% combined chlorine.

(3) Copolymer containing about 92% isobutylene and 8% myrcene with 1.6%combined chlorine. v,

.(4) Copolymer containing about 95 2-1nethylbutene- 1-, 5% isoprene,with 1.3% combined chlorine.

(5) Copolymer containing about 96% Z-methyl butene-l, 4% butadiene-1,3,with 1.7% combined chlorine.

(6) Copolymer containing about 92% isobutylene,--8%

butadiene-l,3, with 2.4% combined chlorine.

(7) Copolymer containing about 98% isobutylene and 2% l-viny-lcyclohexene-l,3 with 0.5% combined chlorine.

(8) Copolymer containing about isobutylene and 15% isoprene with 6%combined chlorine;

In each of the above cases, the chlorinated butyl rubber is satisfactoryin curing ability, adhesion to natural 'rubber, compatibility withnatural rubber and GR-S rubber, the heat aging characteristics are alsosatisfactory. The molecular weight of the copolymer is also notsubstantially degraded. However, in the cases of the copolymerscontaining butadiene and cyclopentadiene there is a tendency towardspremature curing.

Obviously, other examples of copolymers including tripolymers ofisobutylene, dimethyl fulvene and isoprene, or isobutylene, styrene andisoprene, etc. may likewise be employed within-the purview of thepresent invention. The addition of carbon black as the particular fillerprior to vulcanization is an optional embodiment but is preferred unlessthe butyl rubber is to be other than a black rubber, and the use ofstearic acid as a mold release agent in amounts of about -l5% islikewise an optional cmbodiment. The use at meraptobenzothiazoleinamounts of about 0.3-1.5 weight percent is likewiseoptional. Also,- the use of combinations of-zincoxide and sulfur asthevulcanizing medium is intended m-be included-within the purview ofthe present invention. l Y

EXAMPLE 12; f

The following compositions are compounded and vul canized with 12weight-percent sulfur and used in the fabricationof automobile tires.

1) Copolymercontaining 97.5% isobutylene and 2.5% isoprene; i 7

(2)"Same copolymer (1) except that it contains 1.2% combined chlorine;

(3) A mixtureof 70% of (1) and 30% natural rubber,

and a a .7 v r r (4) A mixture of.70%jof (2)- and 30 %-natural1rubber. V1

Optimum- Percent Tensile Composition cure at 300 Elongation Strength,

F. inmin. r .s;1:

From a comparison of the above, it is noted that composition 4 whichcontains bothnatural rubber and chlorinated butyl rubber vulcanizesrapidly, yielding an elastic product having considerable tensilestrength (2350. p.s.i.),'

whereas composition 3 which comprises an admixture of natural rubberwith unchlorinated butylxrubber, upon vulcanization, exemplifies a-verypoor tensile strength (650 p.s.i.). r

In mixed rubber compositeethe chlorinated butyl rubberof thepresent-invention and" natural rubber-or other. synthetic rubbers may bepresent in any desired ratio,-

normally correspon'dingto about IO-90% of either rubber,

although inor'e'or less may be used. Conventional butyl rubber will notco-vulcan-ize with natural rubber and other synthetic rubberssatisfactorily. This-has been one of the principal reasons preventingmore extensive use of butyl rubber. The chlorinatedbutyl rubbercopolymers of the present invention however, which are substantiallysulfides, mercaptobenzothiazoles, benzothiazyl' disulfide and/or about'0-15 parts by weightor'more of quinoid- "type curing agents such asp-dinitroso'benzene, quinone 'dioximes or esters thereof, and/ortogether with suitable activating agents for the above-general type ofrespective cures, such ascertain multivalentmetal oxides, especiallylead oxides, and/or suchaccelerators as above-mentioned or theirequivalents. The general characteristics of the lptlasticizer oil may beas follows:

Preferred J Minimum Maximum I 525 7 300 700 .15- V 10 so 100-12,000 50"20,000"

i plasticizers suitablein special instances are tars,

waxes, resins, esters, high boiling hydrocarbon oils,

' ganic phosphates, etc.

Examples of antioxidants are 'phenyl-beta-n'aphthylamine or certainalkylated aromatic hydrocarbons or alkylated heterocyclics which may beemployed in amounts of about 0.1% to about 2% by weight depending uponthe particular antioxidant. -For example, alkylated bis-phenols havebeen found particularly ad- I vantageous-as have alkylated aminophenolsand alkylated diphenylamines. The alkyl groups generally do not containmore than about 16 carbon atoms.

EXAMPLE 13 General Specific Range, parts Composiby weight tion, parts byweight Chlorinated butyl rubber (containing 1.3% chlorine).-- 100 FTitanium dioxide. 10-150 40 Zinc Oxide.. 5-100 7 30 Sulfur ,O-4 22-mercaptobenzothiazole.. 0-2 1 Ultra-marine blue 0-1 0.3 Diphenylguanidine- 0-1 0. 3 Stearlc acid 0-2 1. 5

I The above may optionally be admixedwith var ous amountsofotherrubbers, such as with GRS rubber and/ or natural rubber. v

The following rubbers may be used instead of natural rubber andadvantageously combined with the chlorinated butyl rubber of the presentinvention or with chlorinated butyl rubber'and natural rubber copolymersof such materials as butadiene, isoprene or chloroprene with each otheror with olefinic compounds such asstyrene, acrylonitrile, vinylidenechloride, acrylic acid, vinyl pyridine, vinyl chlorideyacrylic esters,methacrylic acids and esters, etc..- as well as su h m -p ym s Pyisobutylene,polybutadiene, polychloroprene, polyisoprene,

and the like, .or copolymers of the monomeric form of 7 these materialswith each other or any of the above, mixtures thereof, or theirequivalents.

] EXAMPLE 14 Another chlorinatedcopolymer containing 99% butylene and J1% isoprene is compounded as follows:

General This R e, p t E mp e, by weight parts by t,

Chlorinated butyl rubber (0.5% combined chlorine) 100 100 Zinc Oxide..-5-30 5 Carbon Black 10-100 50 Sulfur 0.5-5 2 Tetramethyl thiuramdisultlde. 0-2 0.75 Stearic acid V .V 0-10 1. 5 Mineral filler 0-100 0The above composition is then vulcanized for 20 utcs at 300 F. and theresulting vulcanizate has a ten- EXAMPLE l5 'tion proceeded at roomtemperaturefor. two hours, the

"chlorinated butyl rubber was recovered according to the 15 procedure ofExample 4, Run 2, and was analyzed and found to contain: 4

Percent 01 Percent S The above results indicate that the reaction is onepredominately of chlorination rather than of sulfochlorination. EXAMPLE16 Parts by Weight Composition Composition Chlorinated butyl rubber 100Natural rubber Carbon Black (EPC Black) 50 50 Zinc Oxide 5 Stea-ricAcid"- -1 Sulfur 2 Mercaptobenzothiamlp 0. 5 Tetramethyl thiuramdisulfideu 0. 2

Test results were as follows:

. Cure Tune Tensile Percent Composition at 287 F. Strength Elongation(minutes) .s.i.)

The above data show that the chlorinated butyl rubber of the inventioncures effectively with zinc oxide although sulfur may also be included,as may other conventional butyl rubber vulcanization accelerators knownin the art. The data also show that good vulcanizates may be obtainedfrom mixtures of chlorinated butyl rubber with natural rubbenthe tensilestrength and elongation .being almost the same when either chlorinatedbutyl rubber per se is vulcanized or an admixture of chlorinated butyThe remaining construction of the tire may vary according toconventional fabrication, but in general the tire is a multi'layeredtype of structure with an outer layer as above-mentioned. The layer nextadjacent the outer layer generally comprises a carcass 15 which includesa rubber which has incorporated therein a fabric com posed of aplurality of cotton, rayon or nylon cords, etc. The tire also includesan inner lining advantageously made from rubber, e.g. chlorinated butylrubber, which must be substantially impermeable to air- For exam ple,the lining may advantageously comprise natural ruly ber, neoprene-typerubber, a rubbery copolymer, ch10: rinated copolymer or mixtures of anyof the above wherein the copolymer comprises the reaction product ofabout 20-995 weight percent of a C -C isoolefin, such as isobutylene,and about 05-80 weight percent of a C C multi-olefin, such as isoprenewhich has been .atleast partially vulcanized. The above multi-layers, atleast three in number, are conventionally bonded or otherwise adheredtogether, for example, by cementing and/ or es-' pecially byvulcanization, etc., to form a.tire of a unitary structure.

The chlorinated butyl rubber composition of the present invention may beemployed generally throughout the tire and may be used alone or inadmixture with natural rubber or certain synthetic rubbers to includechloroprene rubber, polyisoprene, butadiene or isoprene vinyl pyridinecopolymers, and particularly GRS rubber, etc. However, for the innerlining of the tire, ordinary butyl rubber, chlorinated butyl rubber,natural rubber or mixtures thereof is preferred. Also, whereas the innerlining may comprise chlorinated butyl rubber or ordinary butyl rubber ormixtures thereof, the other layers of the tire, such as the intermediatecarcass layer and/or the outer layer (including the tread area, thesidewall and the outer bead portions, etc.), may comprise chlorinatedbutyl rubber and/or other conventionally employed rubbers, such asnatural rubber and synthetic nlbbers and mixtures thereof (and reclaimedmixtures thereof) especially to include GRS rubber and/or naturalrubber.

A tubeless tire may comprise a casing of an outer layer including thetread, sidewall, outer bead portions, etc., of vulcanized chlorinatedbutyl rubber, natural rubber, or GRS rubber or any mixtures or reclaimedmixtures of these rubbers which have been covulcanized. It alsopreferably comprises an intermediate layer or carcass of the aboverubbers or combinations thereof, especially to include compositionscontaining'chlorinated butyl rubber, alone or in admixture with ordinarybutyl rubber,

natural rubber, GR-S rubber or combinations thereof.

' The tire also comprises an inner layer which is preferably rubber andnatural rubber is vulcanized.

One particularly advantageous use for the chlorinated butyl rubber ofthe present invention is in pneumatic tires of either the inner tubecontaining variety or in a "tubeless type tire.

Figure V depicts a pneumatic tubeless tire which comprises a hollowtoroidal type member which is substantially U-shaped in cross-section byvirtue of an open port ion which extends around the inner periphery ofthe member. In other words, the tire is of a tubular type structurewhich has a cross-section in the form of an open-bellied body withspaced terminal portions to 'define a member generally resembling ahorseshoe. "The terminal portions constitute the bead portions 1 1-11of.

. or without added sulfur.

chlorinated butyl rubber but may be either ordinary butyl rubber alone,chlorinated butyl rubber alone, or an admixture of chlorinated butylrubber and ordinary butyl rubber, which has been at least patriallyvulcanized by' heating for about 3-60 minutes or more at about -'350 F.or higher with about 0.210.0 weight percent sulfur on a basis of theweight of the total rubber or rubbers as hereinbcfore-mentioned or whichhas been cured with any of the heretofore disclosed curing compositions,especially to include curing compositions'comprising or consistingessentially of certain bivalent metal oxides, such as lead oxide orpreferably zinc oxide with While there are above described a numberof'specific embodiments of the present invention, it'is obviously.possible to produce other embodiments and various equivalentmodifications and variations thereof without departing from the spiritof the invention or the scope of the appended claims. a What is claimedis: I l. A composition comprising a substituted-chlorinecontainingisoolefin-multiolefin butyl rubber copolymer,

-the chlorine combined in said copolymer being present of .the firewhich is adjacent lthe said area 13 of the tire. ya

in an amount of at. least about 0.5 weight percent based .on ,copolyrnerbut not act tees .stantially all-of said chlorine combined inthe'copolymer .being .present as substituted-chlorine, wherein the .com-

lchlorine 'has replaceda hydrogen atom toriginally ,pr lesentin saidcopolymer.

'2. A composition according to claim 1 in which the Iisoole'finmultiolefin butyl rubber copolymer comprises a copolymer ofabout 85 to 99.5 weight percent of a C to C isoolefin and about 0.5 toweight percent of a C to C multiolefin.

3. A composition according to claim 1 containing, in addition to thechlorine-containing copolymer, a highly unsaturated rubber selected fromthe class consisting of natural rubber, rubbery diene-styrene copolymersand mixtures thereof.

4. A rubber tire having a tread area, sidewall areas, a carcass area andan interior air-holding area, said tire containing therein thecomposition of claim 1.

5. In a process for manufacturing a tubeless tire including a carcassmember, the improvement which comprises vulcanizing to said carcassmember an air-holding layer disposed interiorly thereof, said layercomprising the composition of claim 1. V

6. A vulcanizable composition according to claim 1 comprising 100 partsby weight of the chlorine-containing copolymer compounded with about 5to 50 parts by weight of zinc oxide, about 0.5 to 5 parts by weight ofsulfur and about 0.3 to 5 parts by weight of an accelerator.

7. A composition according to claim 6 which has been vulcanized byheating at a temperature, levelof between about 250 and 450 F. for about5 minutes to 5 hours.

8. A composition comprising a substituted-chlorinecontaining rubberyisoolefin-multiolefin copolymer, said copolymer containing about 85 to99.5 weight percent of a C to C isoolefin and about 0.5 to 15.0 weightpercent of a C to C multiolefin, the chlorine combined in said copolymerbeing present in an amount of at least about 0.5 weight percent based oncopolymer but not more than about X weight percent combined chlorinewherein X" equals:

(100-L) M1+L(M2+35.46) X 100 and L=mole percent of the multiolefin inthe polymer M =molecular weight of the isoolefin M =molecular weight ofthe multiolefin, and

35 .46=atomic weight of chlorine,

substantially all of said chlorine combined in the copolymer beingpresent as substituted-chlorine, wherein the combined chlorine hasreplaced a hydrogen atom originally present in said copolymer.

9. A composition according to claim 8 in which the isoolefin isisobutylene and the multiolefin is isoprene.

10. A composition according to claim 8 containing, in

percent of the multiolefin, said niultiolefin containing about 4 to 6carbon atoms.

13. A vulcanizable composition according-to claim 8 in which 100 partsby weight of the chlorine-containing copolymer has been compounded withabout 5 to 100 parts by weight of zinc oxide.

14. A process for producing chlorine-containing isoolefin-multiolefinbutyl rubber copolymers which comprises contacting .anunchlorinatedbutyl rubber copolymer with a chlorinating agent at a temperatureilevelof between about 20 and 100 C. until .there'is combined in thecopolymeratjleast 0.5 weight percent chlorine'vbut not more than about 1 atom ofcombined chlorine jper double bond in the copolymer.

15. A process according to claim 14 wherein the butyl rubber .comprisesa copolymer containing about 85 to 99.5 weightpercent of a C 1Qflsoolefin and about 0.5 to 15.0 'Weight percent of a C to C conjugated.diolefin, .the .chlorinationbeing eflected by a'chlofinat- (100L)M +L(M+35.46) X 100 and:

L=mole percent of the diolefin in the copolymer M =molecular weight ofthe isoolefin M =molecu1ar weight of the diolefin, and

35 .46=atomic weight of chlorine.

16. A process according to claim 14 in which the chlorinating agentcomprises gaseous chlorine.

17. A process according to claim 14 in which the.

chlorinating agent comprises liquid sulfuryl chloride.

18. A process according to claim 14 in which the chlorination process isperformed in'the substantial absence of polar solvents.

1'9. A process according to claim 14 in which the chlorination iseffected substantially at room temperature.

20. A process according to claim 14 in which the butyl rubber copolymeris dissolved in a solvent prior to chlorination.

21. A process of vulcanizing a chlorinated isobutyleneisoprene butylrubber copolymer as defined in claim 1, which comprises compounding thechlorinated copolymer with about 10 to 100 partsby weight of a filler,about 5 to 50 parts by weight of a bivalent basicmetal compoundcurative, and vulcanizing the resulting composite at about 250 to 450 F.for between about 5 and 120 minutes.

'22. A'vulcanized rubbery composition comprising asubstituted-chlorinecontaining isobutylene-isoprene butyl rubbercopolymer, the chlorine combined in said copolymer being present in anamount of at least about 0.5

, weight percent based on copolymer but not more than about 1 atom ofcombined chlorine per double bond in the copolymer, substantially all ofsaid chlorine combined in the copolymer being present assubstituted-chlorine, whereby each combined chlorine atom has replaced 7a hydrogen atom originally present in said copolymer,

parts by weight of said chlorine-containing copolymer having beenvulcanized in the presence of about 5 to 50 parts by weight of a basicmetal compound at about 280 to 350 F. for from about 5 minutes to about2 hours.

23.- A process for producing chlorine-containing isoolefin-multiolefinbutyl rubber copolymers which comprises contacting an unchlorinatedbutyl rubber copolymer with, a chlorinating agent at a temperature levelof between about 20 and 100 C. until there is combined in the copolymerat least 0.5 weight percent chlorine but .not more than about 1 atom ofcombined chlorine per mer with a chlorinating agent selected from thegroup consisting of gaseous chlorine, liquid sulfuryl chloride andmixtures thereof, at a temperature level of between about 20 and 100 C.until there is combined in the copolymer at least 0.5 weight percentchlorine but not more than about 1 atom of combined chlorine per doublebond in the copolymer.

References Cited in the file of this patent- UNITED STATES PATENTS 20Frolich et al. May 25, 1948 Lightbown et a1 4.. Apr. 12, 1949 BriantJan, 8, 1952 Herzegh Feb. 26, 1952 Crawford et a1. Mar. 17, 1953Morrissey et a1. Dec. 28, 1954 Morrissey et al. Jan; 24, 1956 HallenbeckAug. 27, 1957

1. A COMPOSITION COMPRISING A SUBSTITUTED-CHLORINE CONTAININGISOOLEFIN-MULTIOLEFIN BUTYL RUBBER COPOLYMER, THE CHLORINE COMBINED INSAID COPOLYMER BEING PRESENT IN AN AMOUNT OF AT LEAST ABOUT 0.5 WEIGHTPERCENT BASED ON COPOLYMER BUT NOT MORE THAN ABOUT 1 ATOM OF COMBINEDCHLORINE PER DOUBLE BOND IN THE COPOLYMER, SUBSTANTIALLY ALL OF SAIDCHLORINE COMBINED IN THE COPOLYMER BEING PRESENT ASSUBSTITUTED-CHLORINE, WHEREIN THE COMBINED CHLORINE HAS REPLACED AHYDROGEN ATOM ORIGINALLY PRESENT IN SAID COPOLYMER.